Hi guys Bit of an essay i'm afraid.....

Bought myself another classic WRX after a long wait and i'm pretty much happy with it.

The car has been fully decated with a full system and has a HKS mushroom filter.

I've had 2 WRX's the first being an L reg which was decated but had the standard airbox and DV and the second being an M reg which just had a Magnex 6x4 backbox.

My L reg was very quick to spool up and quick but lacked the top end pull which is pretty much what i thought a lower powered scooby was like compared to say an STI with 300 brake etc.

My M reg was slower but still quick ish and had the same sort of top end power.

Now to my N reg example.

This thing is proper noisy! It sounds awsome probably due to the combination of decat and the HKS filter.I must admit i'm not a fan of atmospheric DV's and refused to put them on my last 2 but my one now sounds like it has one even though it has the standard recirc! It sounds like there is air leaking even under normal driving and sounds like a jet taking off.

If you floor it it takes what seems like forever to get going..what i presume turbo lag should feel like..BUT if it has been fully decated so shouldn't it spool really quickly?? On the boost gauge it sits at 0 until about 3.5K then sits at 10 till maybe at say 4.5k then flies up to 14 psi! If i remember the standard psi should be 12?

Once it starts to come on boost if flies!!! If i'm honest i'd say it feels like 300 bhp easy.But the thing is i hate the fact it takes so long for the boost pressure to reach the top.I think my first scooby just shot up to 13 PSI then sat there through the rev range.

Looking through the history/receipts etc i found one for a Boost controller off EBAY but i can't see one fitted either in the engine bay or in the cockpit

I have the cash ready for a remap but if there is somthing wrong with the car i'd rather get it sorted before i shell go ahead with it.I havn't had a chance to look at the ECU yet so maybe it has been messed with a bit?

Any help appreciated

 

RE: boost controller. If it has one fitted it should be easy to find it. The Boost control solenoid on the drivers side inner wing will have been bypassed, simply follow the hoses.

 

Sounds like a boost leak somewhere to me. Check all connections from the turbo, to the intercooler, in to the engine. Watch the pipe and gasket under the intercooler.

 

if you know some one with a dump valve just borrow. Yours may be faulty. Is it a bailey by any chance?

 

Boost shouldn't sit at 0 until 3,500rpm
it should be steadily rising and to be honest should be pretty much at full boost by 3,500rpm especially in 4th/5th.
You should get above 0 at 1/4 throttle.

could be a boost leak but could also be a cracked up-pipe that will cause spool to be delayed.boost control could be sticking, actuator could be faulty etc..etc.... a whol host of things really.
Could just be that they removed the boost controller and plumbed all the pipes in wrong.

boost controlpipework should be as below :


IMHO HKS Mushroom is poor. I have seen a number of dirty MAF's and even failed MAFs that run the HKS Mushroom.

 

Also forgot to mention it's a bit poor starting from cold...not that it dosn't start it just takes a few prods of the throttle for the revs to rise to 1000 then it settles in a few seconds...heard this happens with some MAP's??

Thanks for all the advise guys.It still has the standard DV btw.

I did have a good look around the solenoid etc but can't seem to find any split hoses etc i think it must be an air leak somwere because on 1/4 throttle i can hear hissing and the boost sits at 0 for some time and creeps in a funny way.I'll take some pipes off on monday and have a better look around the bay.

 

Also at idle with no throttle it sits at -30 or somthing then if i stab the throttle it shoots up to just under zero.

When pulling off it sits at 0 until about 3.5K revs then rises to about 5 PSI then at about 4.5K it shoots up to 14PSI and the explodes with power rather than it being progresive That's the best way i can describe the problem.

 

I have just fitted a dump valve to my car and had exactly the same problem ... It turned out to be a boost leak ... When I went hard on the gas there was a loud hissing and then suddenly the boost would hit and the car would take off like a rocket.
I traced the problem to a bad seal where I had connected the dump valve elbow. I would suggest that you have a boost leak somewhere.

 

Yeah mate i'm pretty sure it is now I hate the way it drives but the sound is sweet! lol